Steam-generator



(No Model.)

1); HARMON.

STEAM GENERATOR.

N0. 313,327. I Patented Mar. 3, 1885.

N, PErEns. PholuLih-oqrzphar. Wnhing on. D, c.

ArsNr Grains.

DEOATER HARMON, OF ION IA, MICHIGAN.

STEAM-GENERATOR.

SPECIFICATION forming part of Letters Patent No. 313,327, dated March 3, 1885.

Application filed September 24, 1884. (No model.)

that class of steam-generators in which the heat generated in the furnace or fire-chamber is retained in the boiler or generator until it has parted with all or nearly all its caloric. In such constructions, so far as I am aware,

there, has been but a single return-bend flue,

and the connection of such flue with the firebox has been at or near the top thereof instead of near the bottom, and the greater part of the flue has been above the top of the firebox. This has been found objectionable, first, because with a single return-bend the heat generated in the furnace would pass off at the smoke-pipe before it had parted with all of its calorie; and, second, because where the flue is almost all above the furnace in order to use a large furnace the boiler has to be made much larger, and there is consequently a much larger water-space than where the flue is arranged below the top of the furnace.

The object of my invention is to avoid these difficulties; and to these ends the invention consists in the peculiar combinations, and the construction and arrangement of parts hereinafter more fully described and claimed.

Figure 1 is an elevation of a locomotiyeboiler with the flue-shell partially broken out in order to show the interior arrangement. Fig. 2 is a vertical cross-section through such flue.

In the accompanying drawings, which form a part of this specification, A represents the shell of a locomotive-boiler, constructed in the usual manner, except as to its flue system.

B represents the fire-box, and O the smokejacket, in which also there is no departure from the well-known manner of construction.

E is a flue nearly rectangular in form, and varied in size to suit the different sizes of generators, care being taken that in its width and length there should be left between its sides and ends and the shell of the boiler sufficient water-space. This flue communicates with the fire-box at one end, passing through the fluesheet, thence nearly to the opposite end of the boiler, returning upon itself nearly to the front again, and then again returning upon itself, and discharges through the rear fluesheet into the smoke stack, care being taken that between the parallel parts of this flue there shall be sufficient water-space. This flue may be stayed in position with relation to the shell of the boiler in any convenient and effective manner, such as is well known to boiler-manufacturers and practical engineers. To prevent this flue from collapsing under the water-pressure, it needs internal staying, and this may be done in the usual manner; but I prefer to employ a series of short vertical tubes, F, set staggering, as shown, and affording communication through the flue with the water-space above and below each of the parallel sections, because this not only furnishes a means for staying the flues internally, but also affords means for a more rapid discharge of the calorie and for a complete circulation of the water within the boiler,

so that there is less liability of incrustation forming in such boiler.

It will be noticed that the sides of the flue are rounded, so as to embody the principle of the arch, whereby they withstand the pressure in this direction, and need no internal stays.

The front and rear flue-sheets of a boiler constructed upon this plan may be provided with suitable plug-openings, through which a stream of water may be forced to clean off the flat top portions of this flue; or, if an incrustation should form thereon, a suitable tool or scraper may be used for the purpose of removing it. By this construction it will readily be observed that the products inpassing through the fire-box of the smoke-stack are compelled to take such a circuitous course as to part with all or nearly all the caloric before leaving the boiler, and that the amount of radiating surface of the horizontal and vertical tubes is sufficient to accomplish this result, provided such flue is made to correspond with the size of the shell. The strength of the flue-sheets is preserved by having but one opening cut in each, while as now constructed a large number of openings are made, exposing connections between fines and the fluesheets to the direct action of the fire, and the liability of these connections to leak and give out is too well known to all practical engineers to require any further comment.

In putting in the short vertical tubes into the large flues these should be so put in, in ways well known to boiler-makers, that the joints or connections are at all times in contact with the water, so that every joint is protected. from the fire by such water-contact.

It will readily be seen that should, as frequently happens in all steam'generators, the fiue-sheets, especially the one in the rear of the fire-box, be burned out it is avery simple matter to repair the boiler by removing such flue-sheet and substituting another, as'there is but one connection to be made between such flue-sheet and the flue, instead of the large number now required to be made.

I am aware that it has been. proposed to employ a flue in the form of the letter S for conveying air from the fire-box to a cistern,

' for the purpose of heating the water in said cistern; but in such construction the end of the flue connected with the fire-box was higher than its discharge end, and the heated air had to be forced down. By my construction, wherein the discharge end of the flue is higher and its opposite or receiving end the lower, the products of combustion will be discharged more readily and without any artificial draft, as is required in the former construction.

\Vhat I claim as my invention is- In combination with the shell of a boiler, its firebox and smoke-jacket,'arranged at opposite ends thereof, and its front and rear fluesheets, the flattened flue E, in the form of a flattened letter, 8, connected with the lower part of the fire-box at one end, and after returning upon itself twice discharging at a point higher than its connection with the firebox through the rear flue-sheet into the smoke jacket, the discharge end of said flue being substantially in line with the top of the firebox, said flue having rounded sides to with stand steanrpressure, and having its top and bottom stayed against the same by the vertical tubes F, set staggering, as shown, thereby furnishing a means for the more rapid discharge of the calorie, and a complete circulation of the water within the boiler, substantially as and for the purposes specified.

DEOATER HARMON.

\Vitnesses:

H. S. SPRAGUE, E. SoULLY. 

